In accordance with greater integration and increased speed of semiconductor devices, wiring patterns have been miniaturized, and the reduction of parasitic capacitance generated by an insulation film between wirings has become increasingly important. In order to reduce parasitic capacitance generated by an insulation film between wirings of a minute wiring pattern, various organic materials of low dielectric constant have been developed in recent years. These organic materials have been used to form an insulation film between layers and a protective film as a Low-k material. This Low-k film material is known to form an SOD film by applying the same to a surface of an object to be processed by means of a spin coater and baking furnace. However, many of the SOD films are made of an organic material, and some of the SOD films are inferior in mechanical strength. This is because a high porosity is employed to obtain a low dielectric constant. Thus, an electron beam processing apparatus has been used to try to modify qualities of the SOD film, such as enhancing mechanical strength, while maintaining a low dielectric constant thereof.
An electron beam processing apparatus irradiates electron beams from a plurality of electron beam tubes onto a surface of an object to be processed such as a wafer to modify and cure a film such as an SOD film on the surface of the object to be processed. Such modification and curing is referred to as an “EB cure” below. The EB cure is carried out by setting processing conditions (process time, for example) of the electron beam processing apparatus, with reference to back data previously obtained by evaluating a film of the same kind.
In modifying a film quality by using a conventional electron beam processing apparatus, even when processing conditions such as a process time of the electron beam processing apparatus are set based on a previous evaluation, it is difficult to achieve the most suitable process time because of an uniform amount of irradiation of electron beams onto an object to be processed. That is, even with the same process time, the amount of electron irradiated onto an object to be processed may be either too much or too little. Thus, it is difficult for a film on a surface of the object to be processed to obtain a desired film quality, which results in a reduction of throughput. For example, if a process time for the EB cure is insufficient, curing is not completed and a desired film strength cannot be achieved. Thus, a suitable film quality cannot be obtained. On the other hand, an excess processing time for the EB cure degrades the k value, and thus a suitable film quality cannot be obtained.